Since PC4000 isn't an official memory standard, obviously going higher than 250MHz is going to be unsupported by all but the most confident manufacturers. To avoid endless customer support calls and needless Return Merchandise Authorization costs, the memory manufactures are practicing the well known act of binning. This applies to memory in the following way: Memory is assembled and tested under a defined set of parameters. That which passes, is sold with its intended rating. Of the memory that passes at the "PC4000 mark" more tests are done to deduce the memory's maximum stable speed and if the memory can withstand a 266MHZ front side bus, it is labeled and sold as PC4300. To reduce support calls and RMAs, stringent hardware requirements are typically imposed by the manufacturer to further reduce the chances of end-user issues. More often than not, this is a list of compatible motherboards that have been tested under a typical configuration to pass stress testing. If you don't see your motherboard on the list of compatible configuration, and you buy this RAM, you are taking your own chances and Kingston, nor Club Overclocker will be responsible. Motherboards, while based on the same chipset, are not made to the same quality specification. All throughout COMDEX 03 I heard one motherboards make and model constant mentioned as having the best memory compatibility. Likewise, the Asus P4C800-E Deluxe is listed as being compatible with Kingston PC4300.

Features

• Power supply : Vdd: 2.7V ± 0.1V, Vddq: 2.7V ± 0.1V
• Double-data-rate architecture; two data transfers per clock cycle
• Bidirectional data strobe (DQS)
• Differential clock inputs (CK and CK)
• DLL aligns DQ and DQS transition with CK transition
• Programmable Read latency 3 (clock)
• Programmable Burst length (2, 4, 8)
• Programmable Burst type (sequential & interleave)
• Timing Reference: 3-4-4-8-1 at +2.7V
• Edge aligned data output, center aligned data input
• Auto & Self refresh, 7.8us refresh interval(8K/64ms refresh)
• Serial presence detect with EEPROM
• High Performance Heat Spreader
• PCB : Height 1.250” (31.75mm), double sided component

Testing

     Using an Asus P4C800-E Deluxe, I ramped up with a known high-speed processor, my Pentium-4 2.4"C" to find the maximum headroom of this memory. Since the memory is labeled as PC4300, the bus speeds started at 266. I then added one MHZ to the front side bus, kept the CPU to memory ratio at 1:1 and continued to climb until the system crashed.

Conclusion

     The Kingston Hyper-X PC4300 operates very smoothly at 266MHz and even 267Mhz, but fails to Overclock to any bus speed beyond that point. Considering the RAM is already overclocked, I am quite impressed with the stock operating voltage of this memory: 2.7 volts. Increasing the voltage to 2.8v did not help gain any high operating speed, or allow me to tighten the memory timings. Generally, we've seen most PC4000 and PC4300 come into Club Overclocker wanting at least 2.8 Volts vDIMM. I had hopes that this lower voltage requirement would translate into higher overclocking headroom.